Rigid-Flexible Composite Microspheres for High-Temp Drilling Plugging

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Solution Overview

Problem

Existing plugging agents in oilfield drilling fluids fail to effectively resist high temperatures and high salinity conditions, leading to issues like borehole wall collapse, lost circulation, and reservoir damage, which hinder oil and gas exploration and result in economic losses.

Innovation Solution

A high temperature and high salinity-resistant complementarily rigid-flexible plugging agent is developed, comprising composite microspheres with a rigid nano-silica core and a flexible polymer shell derived from copolymerization of temperature-resistant monomers and divinyl benzene, using a RAFT chain transfer agent to control particle size and enhance temperature and salt resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If flexible organic materials are used as plugging agents, then the plugging agent can adapt to formation fractures and pores, but the temperature resistance and salt tolerance are poor

Engineering Contradiction:

Improveadaptability to formation fracturesVSAvoidtemperature resistance and salt tolerance

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent uses composite microspheres comprising a rigid inorganic core (silica, calcium carbonate, or barium sulfate) coated with a flexible polymer shell (styrene-butadiene rubber or nitrile rubber). This composite structure combines the high temperature and salt resistance of the inorganic core with the adaptability and deformability of the organic shell, allowing the plugging agent to withstand downhole conditions while effectively plugging fractures and pores.

Inventive Principle:

Principle #40Composite materials

2Reliability

If rigid materials are used as plugging agents, then the resistance to high temperature and high salinity is strong, but the plugging effect is not satisfactory due to inability to match pore and fracture shapes

Engineering Contradiction:

Improveresistance to high temperature and high salinityVSAvoidplugging effect

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The composite microspheres combine a rigid inorganic core providing temperature and salt resistance with a flexible organic shell that can deform to match the irregular shapes of formation pores and fractures, thereby achieving both environmental resistance and effective plugging.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The flexible polymer shell (styrene-butadiene rubber or nitrile rubber) coating the rigid core can elastically deform to conform to the complex geometries of formation pores and fractures, enabling the plugging agent to effectively seal irregular pathways while the rigid core maintains structural integrity under high temperature and salinity conditions.

Inventive Principle:

Principle #30Flexible shells and thin films

3Ease of manufacture

If existing plugging agents are used in high temperature and high salinity environments, then the drilling fluid can be formulated, but the plugging agents fail and cause downhole troubles

Engineering Contradiction:

Improvedrilling fluid formulationVSAvoidplugging agent performance

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The composite microspheres with inorganic cores and organic shells maintain their plugging functionality in high temperature and high salinity environments, preventing the failures that occur with conventional plugging agents and avoiding downhole troubles such as borehole wall collapse, lost circulation, and reservoir damage.

Inventive Principle:

Principle #40Composite materials

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The plugging agent demonstrates excellent dispersion and plugging properties at 240°C and high salinity, reducing filtrate loss and forming an effective pressure-bearing plugging layer, thereby preventing pressure transmission and filtrate invasion, and improving the adaptability to formation fractures.

Implementation Method 1

the flexible material comprises a polymer derived from copolymerization of water-soluble temperature-resistant monomer, oil-soluble temperature-resistant monomer and divinyl benzene co-monomer

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

The plugging agent is a dispersion emulsion comprising composite microspheres

Methodology Applied

Scientific EffectDispersion: Dispersion (of waves)

Data Source

PatentUS11970655B2High temperature and high salinity-resistant complementarily rigid-flexible plugging agent and method for preparing the same and water-based drilling fluid and use thereof

Publication Date: 2024.04.30 CHINA UNIV OF PETROLEUM (EAST CHINA)

AI summary

A high temperature and high salinity-resistant complementarily rigid-flexible plugging agent, a method for preparing the same, and a water-based drilling fluid and a use thereof.